The three-level portion of the addition is connected to the main house by a lower wing.

The government official and his wife prefer their homes to be as progressive as their politics. Their weekend house on 100 acres near Fredericksburg, Virginia, is an unusual Art Moderne structure with glass-block bays and porthole windows. But while the streamlined residence met their immediate family needs, it didn’t offer places to view the nearby Rappahannock River or host their frequent overnight visitors. So they turned to Bethesda architect Mark McInturff, who had renovated their home outside of DC, to expand the country retreat.

McInturff's addition includes a kitchen with white-painted brick walls, steel windows and cabinets from Bulthaup.

McInturff added a new wing off the side of the 1930s house to provide guest suites and outdoor rooms, as well as more casual living spaces for the owners and their three daughters. His clean-lined design complements the older modern residence while punctuating its compact two stories with an exclamation mark formed by a guest suite atop a tall porch. “I was respectful of the existing house but treated the addition in a more abstract way,” says the architect.

On the ground floor of the new wing, McInturff framed a kitchen and adjacent family room with unadorned walls of white-painted brick and steel windows to repeat elements of the original home. Metal and linoleum-covered cabinets, marble countertops and stainless-steel appliances update the streamlined Art Moderne look. A long, wooden dining table set with simple benches designed by McInturff is as spare as the architecture.

McInturff designed the addition with glass block to match the original 1930s house.

At the far end of the kitchen, the family room is raised on a wooden platform to create a cozy sitting area before the fireplace. The adjacent two-story screened porch is enclosed by louvers at the top and furnished with wicker chairs and a concrete-topped table to supply another living room in warm weather. A stone-paved patio set between the porch and existing house is well situated near the kitchen and dining spaces, and oriented to the river.

Upper-level guest rooms flank a sunny stair hall at the front of the new wing that incorporates glass bricks in the spirit of the original house. From a pair of suites on the second level, a narrower set of stairs leads to a third-floor bedroom under a barrel-vaulted, copper roof. The self-contained aerie opens to a small bathroom and a balcony facing the river.

A patio extends between the porch and existing house to provide an outdoor living/dining space.

Several years after completing the addition, the couple decided to create “a getaway from their getaway,” as McInturff describes his latest design of a pool house and guest quarters situated between the house and the river. “It’s completely self-sufficient so visitors can stay here without the owners having to be around,” he explains of the building, completed in 2009 with help from project architect Colleen Gove Healey.

The largely open-air structure is sited next to an existing swimming pool that extends toward a bend in the Rappahannock below the property. Aligned with the edges of the pool, it is angled away from the house so its place within the landscape is accentuated. “We treated it in the spirit of 18th-century farm dependencies and summer kitchens where meals can be prepared outdoors,” says McInturff. However, far from being traditional, the pavilion is reduced to a skeletal structure of steel. Its white-painted brick piers harmonize with the main house. A cladding of îpe, a Brazilian hardwood, prevents the contemporary structure from appearing too cold.

The family room with its chimney is situated between the porch and the glass-lined stair hall.

Next to the pool, a low fieldstone wall was preserved and used to divide the public and private parts of the new structure. A gap between the two portions, framed by the brick piers, marks the entranceway to the complex.

The open part of the building extends from a wood-framed galley kitchen to face the pool. All the indoor conveniences are here, including a gas grill, a sink, a dishwasher and a refrigerator tucked under the concrete countertop. Along with the kitchen, a living-dining area stretching toward the water is raised on a wooden platform in much the same way as the family room is positioned in the addition. Furnishings include the lean modern chaise designed by Richard Schultz in the 1960s for Knoll. A row of the recliners along the bluestone-paved pool deck invites swimmers to stretch out just beyond a sunken hot tub at the edge of the living area.

A passageway leads to the open-air living/dining area and pool.

Though unencumbered, the outdoor space is shaded from the sun by a slanted roof clad in îpe and stucco and supported by steel. This upturned canopy reaches across the two sides of the complex to direct the view toward the river. In the open-air living/dining area, timber louvers, resembling those of the home’s screened porch, extend under the roof to offer additional solar control. Hanging ceiling fans provide a breeze during hot summer days.

Brick piers and louvers set between steel beams and columns frame the area next to the hot tub and pool.

On the other side of the stone entrance wall, the enclosed portion of the structure is also covered in îpe and divided into two small pavilions. The section closest to the house offers a spacious outdoor shower screened by a stucco-clad, curved enclosure. An adjoining changing room is fitted with laundry facilities.

A small passageway separates this structure from the guesthouse, which offers access to a private garden and roof deck. Just inside the door to the suite is a powder room for pool-goers that can be closed off from the adjacent bedroom and bathroom. Rising up the side of the pavilion, a staircase leads to a deck overlooking the river.

The kitchen and living/dining area in front of the pool are shaded by the overhanging roof.

Throughout the pavilions, the architecture is detailed with the utmost precision so its different elements are well connected and crisply expressed. “Fastidious” is how McInturff describes his design, pointing to recesses within the exposed steel beams that were fine-tuned to house stereo speakers. “More and more architects are interested in the skin of buildings,” he says, “but I’m more interested in the bones.”